Question about checking blown speakers, amp, or HU

[FSUNole17 10+ year member]

thanks guys, the sound being put out is just a crackling sound when i give it any sort of volume increase over 25% capacity. At VERY low volumes, it is fine, but when i turn it up to 15 out of a possible 40 volume setting, it just sounds like shart. my setup btw is a pioneer premier 860 HU into a JL 300/2 powering some 2004 model boston acoustic pro 6.5" components.